User-specific confidence thresholds for speech recognition
View Patent ↗A method of automatic speech recognition includes receiving an utterance from a user via a microphone that converts the utterance into a speech signal, pre-processing the speech signal using a processor to extract acoustic data from the received speech signal, and identifying at least one user-specific characteristic in response to the extracted acoustic data. The method also includes determining a user-specific confidence threshold responsive to the at least one user-specific characteristic, and using the user-specific confidence threshold to recognize the utterance received from the user and/or to assess confusability of the utterance with stored vocabulary.
1. A method of automatic speech recognition, comprising the steps of:
(a) receiving an utterance from a user via a microphone that converts the utterance into a speech signal;
(b) pre-processing the speech signal using a processor to extract acoustic data from the received speech signal;
(c) identifying at least one user-specific characteristic in response to the extracted acoustic data, wherein the at least one user-specific characteristic comprises a plurality of confidence scores associated with failed attempts of the user to store a nametag; and
(d) determining a user-specific confidence threshold responsive to the at least one user-specific characteristic, wherein the determination is carried out by calculating an average of the plurality of confidence scores and setting the user-specific confidence threshold to a value greater than or equal to the calculated average.
2. The method of claim 1 , further comprising the step of:
(e) using the user-specific confidence threshold to recognize the utterance received from the user, wherein the user-specific confidence threshold is a recognition confidence threshold.
3. The method of claim 1 , further comprising the step of:
(e) using the user-specific confidence threshold to assess confusability of the utterance with stored vocabulary, wherein the user-specific confidence threshold is a confusability confidence threshold.
4. The method of claim 1 , wherein the step (d) determination is also carried out by first verifying that the plurality of confidence scores are within a predetermined range.
5. The method of claim 4 , wherein the predetermined range is plus or minus five percent.
6. The method of claim 1 , wherein the at least one user-specific characteristic includes at least one formant of the utterance.
7. The method of claim 6 , wherein the user-specific confidence threshold is determined using a multiple regression calculation including the at least one formant of the utterance and at least one formant coefficient developed from a plurality of development speakers.
8. The method of claim 1 , wherein the at least one user-specific characteristic includes pitch of the utterance.
9. The method of claim 8 , wherein the user-specific confidence threshold is determined using a multiple regression calculation including the pitch of the utterance and a pitch coefficient developed from a plurality of development speakers.
10. The method of claim 1 , wherein the at least one user-specific characteristic includes pitch and at least one formant of the utterance, and wherein the user-specific confidence threshold is determined using a multiple regression calculation including the pitch and the at least one formant of the utterance and a pitch coefficient and at least one formant coefficient developed from a plurality of development speakers.
11. A method of automatic speech recognition, comprising the steps of:
(a) receiving an utterance from a user via a microphone that converts the utterance into a speech signal;
(b) pre-processing the speech signal using a processor to extract acoustic data from the received speech signal;
(c) identifying at least one user-specific characteristic including pitch and at least one formant in response to the extracted acoustic data;
(d) determining a user-specific confidence threshold responsive to the identified at least one user-specific characteristics, wherein the determination comprises using a multiple regression calculation including the identified user-specific pitch and at least one formant and a pitch coefficient and at least one formant coefficient developed from a plurality of development speakers; and
(e) decoding the acoustic data based on the user-specific confidence threshold to produce a plurality of hypotheses for the received utterance, including calculating confidence scores for the hypotheses.
12. The method of claim 11 , further comprising the step of:
(f) post-processing the plurality of hypotheses, including using the user-specific confidence threshold to identify at least one hypothesis of the plurality of hypotheses as the received utterance, wherein the user-specific confidence threshold is a recognition confidence threshold.
13. The method of claim 11 , further comprising the step of:
(f) post-processing the plurality of hypotheses, including using the user-specific confidence threshold to assess confusability of the utterance with stored vocabulary, wherein the user-specific confidence threshold is a confusability confidence threshold.
14. The method of claim 11 , wherein the at least one user-specific characteristic of step (c) also includes a plurality of confidence scores associated with failed attempts of the user to store a nametag.
15. The method of claim 14 , wherein the step (d) determination is further carried out by calculating an average of the plurality of confidence scores, and setting the user-specific confidence threshold to a value that is relative to the calculated average.
16. The method of claim 15 , wherein the step (d) determination is also carried out by first verifying that the plurality of confidence scores are within a predetermined range.
17. A method of automatic speech recognition, comprising the steps of:
(a) receiving an utterance from a user via a microphone that converts the utterance into a speech signal;
(b) pre-processing the speech signal using a processor to extract acoustic data from the received speech signal;
(c) identifying at least one user-specific characteristic including a plurality of confidence scores associated with failed attempts of the user to store a nametag;
(d) determining a user-specific confidence threshold responsive to the at least one user-specific characteristic;
(e) decoding the acoustic data to produce a plurality of hypotheses for the received utterance, including calculating confidence scores for the hypotheses; and
(f) post-processing the plurality of hypotheses, including using the user-specific confidence threshold to assess confusability of the utterance with stored vocabulary, wherein the user-specific confidence threshold is a confusability confidence threshold.
18. The method of claim 17 , wherein the step (d) determination is carried out by calculating an average of the plurality of confidence scores and setting the user-specific confidence threshold to a value greater than or equal to the calculated average.
19. The method of claim 18 , wherein the at least one user-specific characteristic also includes pitch and at least one formant of the utterance, and wherein the user-specific confidence threshold is also determined using a multiple regression calculation including the pitch and the at least one formant of the utterance, and a pitch coefficient and at least one formant coefficient developed from a plurality of development speakers.
20. The method of claim 19 , wherein the step (d) determination is carried out by setting the user-specific confidence threshold to a value that is relative to the calculated average or the multiple regression calculated value.